1. Field of the Invention
The present invention relates to an electronic component including a circuit board which is rectangular or substantially rectangular in plan view and in which a component is mounted on at least one principal surface and a plurality of land-shaped mounting electrodes are provided on the other principal surface.
2. Description of the Related Art
In recent years, there has been a demand to further reduce the size of mobile terminals. Also, there has been a demand to further reduce the size and height of electronic components (electronic radio-frequency modules) mounted on motherboards in the mobile terminals, for example, a Bluetooth (registered trademark) module, a wireless LAN module such as a Wi-Fi module, and an antenna switch module for a cellular phone. Such an electronic component includes a circuit board in which components, for example, a semiconductor element such as a transistor, an FET, a diode and an IC, a resistor element, a capacitor element, and an inductor element are mounted on at least one principal surface, and land-shaped mounting electrodes are provided on the other principal surface. Since there is a demand to reduce the size and height of the electronic component, miniaturization of the circuit board included in the electronic component is advancing, and miniaturization of the mounting electrodes provided on the circuit board is also advancing.
As miniaturization of mounting electrodes provided on a circuit board included in an electronic component thus advances, stress, which results from, for example, a twist given to the circuit board when the electronic component is mounted on a motherboard for assembly of a mobile terminal or an impact applied when the mobile terminal including the motherboard on which the electronic component is mounted with solder falls, concentrates at portions of the circuit board in the electronic component where the mounting electrodes are provided. This may cause a fracture, a chip, and a crack in the circuit board. In this case, transmission lines, such as via holes of the circuit board or a wiring pattern provided in the circuit board, may be broken, and this may result in a breakdown of the mobile terminal.
Accordingly, it has been proposed that corners of four mounting electrodes, which are provided close to four corners of a circuit board, closest to the four corners of the circuit board are cut off and chamfered in order to avoid such a fracture, chip, or crack in the circuit board (see, paragraphs [0001] to [0029] and FIG. 1 of Japanese Unexamined Patent Application Publication No. 2005-26312, for example). That is, as illustrated in FIG. 6, of a plurality of rectangular mounting electrodes 502 provided on a principal surface, which is to be mounted on a motherboard, of a circuit board 501 included in an electronic component 500, four mounting electrodes 502 provided near four corners of the circuit board 501 are chamfered at corners closest to the four corners so that a chamfer amount c becomes a/5 to a/2. This reduces the stress applied to the circuit board 501 by an external impact such as a twist applied to the circuit board 501, and prevents a fracture, a warp, and a crack from being caused in the circuit board 501.
When the corners of the four mounting electrodes 502, which are provided near the four corners of the circuit board 501, closest to the four corners of the circuit board 501, are chamfered, as illustrated in FIG. 6, a fracture, a warp, and a crack are prevented from being caused in the circuit board 501 by an external impact. There is a demand to further improve such a technique.